FIELD OF THE INVENTION
[0001] In various embodiments, the present invention relates to methods and compositions
for the treatment of autoimmune diseases or disorders of the immune system, comprising
administering a TACI-Ig fusion protein such as atacicept using a particular dosage
regime which maximizes the blocking of functions of the ligands of the TNF family.
BACKGROUND OF THE INVENTION
The BlyS Ligand / Receptor Family
[0002] Three receptors, TACI (transmembrane activator or Calcium-Modulating Cyclophylin
Ligand-interactor), BCMA (B-cell maturation antigen) and BAFF-R (receptor for B-cell
activating factor, belonging to the TNF family), have been identified that have unique
binding affinities for the two growth factors BLyS (B-lymphocyte stimulator) and APRIL
(a proliferationinducing ligand) (
Marsters et al. Curr Biol2000; 10(13): 785-788;
Thompson et al. Science 200 1 ; 293:2 1 08-2 1 11). TACI and BCMA bind both BLyS and APRIL, while BAFF-R appears capable of binding
only BLyS with high affinity (
Marsters et al. Curr Biol2000; 10(13):785-788;
Thompson et al. Science 2001; 293:21 08-21 11 .). As a result, BLyS is able to signal through all three receptors, while APRIL
only appears capable of signaling through TACI and BCMA. In addition, circulating
heterotrimer complexes of BLyS and APRIL (groupings of three proteins, containing
one or two copies each of BLyS and APRIL) have been identified in serum samples taken
from patients with systemic immune-based rheumatic diseases, and have been shown to
induce B-cell proliferation in vitro (
Roschke et al. J Immunol 2002; 169: 4314-4321). Amongst the Ig-fusion proteins for all three receptors, only TACI-Fc5, such as
atacicept, was able to block the biological activity of the heterotrimeric complexes
(
Roschke et al. J Immunol 2002; 169: 43 14-4321).
Systemic Lupus Erythematosus
[0005] There is no single criteria to diagnose SLE. The American College of Rheumatology
has developed 11 criteria to diagnose SLE, which span the clinical spectrum of SLE
in aspects of skin, systemic, and laboratory tests. These criteria include malar rash,
discoid rash, sensitivity to sun light, oral ulcers, arthritis, serositis, kidney
and central nervous system inflammation, blood alterations, and the presence of antinuclear
antibodies. A patient must meet four of these criteria in order to be classified as
a SLE patient. (
Tan et al. (1982) Arthritis Rheumatol. 25:1271-1277). SLE is usually confirmed by tests including, but not limited to, blood tests to
detect anti-nuclear antibodies; blood and urine tests to assess kidney function; complement
tests to detect the presence of low levels of complement that are often associated
with SLE; a sedimentation rate (ESR) or C-reactive protein (CRP) to measure inflammation
levels; X-rays to assess lung damage and EKGs to assess heart damage.
[0006] The standard therapy for SLE is administration of the steroid glucocorticoid, a general
immune response inhibitor. It can be used to relieve symptoms; however, no cure for
SLE is currently available. Low dose p.o. prednisone at a level less than 0.5 mg/kg/day
is usually given. Unfortunately, this therapy is insufficient to keep patients in
remission, and flaring of the disease is frequent. Flares can be controlled with high
dose glucocorticoid via intravenous pulses at 30mg methylprednisolone/kg/day for 3
consecutive days. However, steroid treatment at high dosage can present severe side
effects for patients.
[0007] These standard treatments are generally nonspecific, are frequently associated with
serious side-effects and do not significantly affect the progression of the disease
or transition to life threatening kidney complications (lupus nephritis or LN). Consequently,
there is a long-felt need in the art to develop new methods for treating SLE.
[0008] US 2007/0071760 describes methods for treating B cell malignancies using a TACI-Ig fusion molecule.
[0011] The present disclosure is directed to methods of treating autoimmune diseases. Illustratively,
the methods disclosed herein including administering to a patient a composition comprising
a human immunoglobulin-constant domain and TACI extracellular domain or a fragment
thereof which binds BLyS and/or APRIL.
[0012] The disclosure comprises methods of treating autoimmune diseases, including SLE,
using a molecule that comprises a fusion of the TACI extracellular domain or any fragment
thereof that retains the ability to bind BLyS and/or APRIL, such as atacicept.
[0013] The disclosure comprises methods of treating SLE comprising administering to a patient
in need thereof an effective amount of a fusion molecule comprising a human immunoglobulin-constant
chain and TACI extracellular domain or a fragment of TACI extracellular domain that
binds BLyS and/or APRIL. In one embodiment, the fragment of the extracellular domain
of TACI comprises one or two cysteine repeat motifs. In another embodiment, the fragment
is a fragment comprising amino acids 30-110 of the extracellular domain of TACI. In
yet another embodiment, the fragment is a fragment comprising amino acids I-154 of
the extracellular domain of TACI (SEQ ID NO: 1).
[0014] The disclosure comprises methods of treating SLE by administering to a patient a
composition comprising a fusion polypeptide, TACI-Fc5, comprising a human immunoglobulin-constant
domain, Fc5, having the sequence set out as SEQ ID NO: 2 and a TACI extracellular
domain having the sequence set out as SEQ ID NO: 1.
[0015] The disclosure comprises methods of treating SLE by administering to a patient a
composition comprising a fusion polypeptide comprising a human immunoglobulin-constant
domain with the sequence set out as SEQ ID NO: 2 and a polypeptide which binds BLyS
and/or APRIL and which is at least about 50%, at least about 60%, at least about 65%,
at least about 70%, at least about 75%, at least about 80%, at least about 85%, at
least about 90%, at least about 95% or at least about 99% identical to SEQ ID NO:
1.
[0016] Other autoimmune diseases can be treated by the methods of the invention by administering
to a patient a fusion polypeptide comprising a human immunoglobulin-constant chain
and TACI extracellular domain or a fragment of TACI extracellular domain that binds
BlyS and/or APRIL. Such autoimmune diseases include, but are not limited to rheumatoid
arthritis (RA), Graves disease, type I and type II diabetes, multiple sclerosis, Sjogren
syndrome, scleroderma, glomerulonephritis, transplant rejection, e.g., organ and tissue
allograft and xenograft rejection and graft versus host disease.
[0017] In one embodiment, the methods of the instant invention comprise administering to
a SLE patient atacicept fusion molecule in amounts from about 0.01 mg/kg of patient's
body weight to about 25 mg/kg of patient's body weight. The atacicept molecule can
be administered repeatedly at predetermined intervals. Illustratively, the molecule
can be administered multiple times during predetermined dosing intervals. For example,
dosing can be of a relatively lower dose of drug at weekly or every three week intervals.
An initial treatment with a Atacicept fusion polypeptide can be followed by administering
the polypeptide on a bi-weekly (every other week) or tri-weekly (every third week)
basis for at least 2 or 3 more additional weeks, respectively. For example, the polypeptide
can be administered on a bi-weekly basis for an additional 2 to 30 weeks. Alternately,
the polypeptide may be administered on a weekly or daily basis.
[0018] According to the methods of the instant invention, atacicept polypeptide can be administered
to a SLE patient subcutaneously, orally, or intravenously and in combination with
other medicaments. Such medicaments include, but are not limited to: NSAIDS (nonsteroidal
anti-inflammatory drugs) both over the counter and those requiring a prescription
such as diclofenac sodium, indomethacin diflunisal and nabumetone; anti-malarials
such as hydroxychloroquine sulfate and chloroquine; corticosteroids such as prednisone,
hydrocortisone, and methylprednisolone; and immunosuppressives such as azathioprine,
cyclophosphamide, methotrexate, cyclosporine, and mycophenolate mofetil, and IVIg,
DHEA, and thalidomide.
BRIEF DESCRIPTION OF THE FIGURES
[0019]
FIGURE 1 graphically represents the free atacicept concentration plotted versus time
in days for subcutaneous administration, a key pharmakinetic measurement. Each line
of the graph is a dosage, as shown in the key.
FIGURE 2 graphically represents the atacicept:BLyS complex concentration plotted versus
time in days for subcutaneous administration, a key pharmakinetic measurement. Each
line of the graph is a dosage, as shown in the key of Figure 1.
FIGURES 3A and 3B graph the biological effects of subcutaneous administration on various
immunoglobulin levels and B cell levels.
FIGURE 4 shows the difference in bioavailability as shown by free atacicept measurements
for subcutaneous and intravenous administration of atacicept.
FIGURE 5 graphs the relatively similar biological activity seen with the two administration
methods, as represented by IgM concentration versus time. See key on Figure 4.
FIGURE 6 graphically shows the similarity between the subcutaneous and intravenous
administration methods, as represented by free atacicept versus time.
FIGURE 7 shows the relatively similar target binding curves seen with the two administration
methods, as represented by atacicept :BLyS complex versus time. See key on Figure
4.
FIGURE 8 graphically shows how multiple doses yield higher biological activity, as
represented by IgM concentration versus time.
FIGURE 9 graphically shows how target binding is higher with multiple doses, as represented
by atacicept:BLys complex versus time. See key on Figure 8.
FIGURE 10 graphically represents the free atacicept concentration plotted versus time
in days for intravenous administration, a key pharmakinetic measurement. Each line
of the graph is a dosage, as shown in the key.
FIGURE 11 graphically represents the atacicept:BLyS complex concentration plotted
versus time in days for intravenous administration, a key pharmakinetic measurement.
Each line of the graph is a dosage, as shown in the key of Figure 10.
FIGURE 12 is a graphic representation of the biomarker measurements using intravenous
administration, specifically immunoglobulin levels and B cell levels.
FIGURE 13A and B are graphic representations of the composite atacicept concentration
(defined as free atacicept + atacicept-BLyS complex) vs time for subcutaneous administration
(Study 1). (A) Single-dose cohorts; (B) Multiple-dose cohorts. Mean ± SE values are
presented. Multiple doses were administered at days 0, 7, 14, and 21. Points during
dosing are not connected to indicate concentration peaks were not captured between
doses.
FIGURE 14A and B are graphic representations of the composite atacicept concentration
(defined as free atacicept + atacicept-BLyS complex) vs time for intravenous administration
(Study 2). (A) Single-dose cohorts; (B) Multiple-dose cohorts. Mean ± SE values are
presented. Multiple doses were administered at days 0 and 21.
FIGURE 15A, B, and C are immunoglobulin summary profiles in Study 1 (subcutaneous
administration) by cohort (% of baseline, mean ± SE). (A) IgM; (B) IgA, (C) IgG. These
figures extend the data presented in Figure 3A and 3B.
FIGURE 16A, B, and C are immunoglobulin summary profiles in Study 2 (intravenous administration)
by cohort (% of baseline, mean ± SE). (A) IgM; (B) IgA, (C) IgG. These figures extend
the data presented in Figure 12.
FIGURE 17A, B, and C graphs the relationship between atacicept subcutaneous dose (Study
1) and the observed maximum immunoglobulin response (in % decrease from baseline).
Bars represent mean± SE. (A) IgM; (B) IgA, (C) IgG.
FIGURE 18A, B, and C graphs the relationship between atacicept intravenous dose (Study
2) and the observed maximum immunoglobulin response (in % decrease from baseline).
Bars represent mean± SE. (A) IgM; (B) IgA, (C) IgG.
FIGURE 19A and B shows IgM profiles (mean± SE) in the same single dose cohorts of
the subcutaneous and intravenous studies. (A) 3 mg/kg; (B) 9 mg/kg.
FIGURE 20A and B shows Atacicept:BLyS complex profiles (mean ± SE) in the same single
dose cohorts of the subcutaneous and intravenous studies. (A) 3 mg/kg; (B) 9 mg/kg.
DETAILED DESCRIPTION OF THE INVENTION
[0020] In various embodiments, the instant invention pertains to methods of treating an
autoimmune disease in a patient by inhibiting interaction of BlyS and/or APRIL with
their receptors. The patient may be a mammal, for example a human. In one embodiment,
the methods utilize an inhibitor that comprises: 1) a polypeptide that comprises a
domain which is at least partially identical to TACI extracellular domain or a fragment
thereof that binds BlyS and/or APRIL; and 2) a human immunoglobulin constant chain.
In one embodiment, the methods of the invention utilize a fusion molecule comprising
a human immunoglobulin constant chain and any polypeptide with at least about 50%,
at least about 60%, at least about 65%, at least about 70%, at least about 75%, at
least about 80%, at least about 85%, at least about 90%, at least about 95% or at
least about 99% sequence identity to TACI extracellular domain.
U.S. Patent Nos. 5,969,102,
6,316,222 and
6,500,428 and
U.S. patent applications 091569,245 and
091627,206 (teachings of which are incorporated herein in their entirety by reference) disclose
sequences for the extracellular domain of TACI as well as specific fragments of the
TACI extracellular domain that interact with TACI ligands, including BlyS and APRIL.
One illustrative fragment of the extracellular domain of TACI comprises one or two
cysteine repeat motifs. Another illustrative fragment is a fragment comprising amino
acids 30-110 of the extracellular domain of TACI or fragments thereof. Yet another
illustrative fragment is a fragment comprising amino acids 1-154 of the extracellular
domain of TACI (SEQ ID NO: 1) or fragments thereof.
[0021] Other fusion molecules useful for the methods of the invention include: a fusion
polypeptide between a human immunoglobulin constant chain and the complete TACI extracellular
domain or its ortholog or a fusion polypeptide between a human immunoglobulin constant
chain and any fragment of the extracellular TACI domain that can bind BlyS and APRIL
ligands. Any of the fusion molecules used in the methods of the invention can be referred
to as a TACI-Ig fusion molecule.
[0022] TACI-Fc5 is one of the TACI-Ig fusion molecules useful for the methods of the invention.
TACI-Fc5 is a recombinant fusion polypeptide comprising the extracellular, ligand
binding portion of receptor TACI from about amino acid 1 to about amino acid 154 (SEQ
ID NO: I) and the modified Fc portion of human IgG, Fc5 (SEQ ID NO: 2). Other TACI-Ig
molecules useful for the methods of the instant invention include a fusion molecule
comprising polypeptide with SEQ ID NO: 2 and a polypeptide which can bind BlyS and
which is at least about 50%, at least about 60%, at least about 65%, at least about
70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%,
at least about 95% or at least about 99% identical to SEQ ID NO: 1.
[0023] Embodiments of the instant invention comprise methods of using a TACI-Ig fusion molecule
for treating SLE. Other autoimmune diseases that can be treated with the methods of
the invention include rheumatoid arthritis (RA), Graves disease, type I and type II
diabetes, multiple sclerosis, Sjogren syndrome, scleroderma, glomerulonephritis, transplant
rejection, e.g., organ and tissue allograft and xenograft rejection, graft versus
host disease or any other autoimmune disease that may be treated by decreasing the
number of circulating mature B cells and immunoglobulin-secreting cells and soluble
immunoglobulins associated with such diseases.
[0024] Embodiments also comprise methods of treatment by administering to a patient a fusion
molecule comprising a human immunoglobulin-constant domain and a polypeptide comprising
any fragment of TACI extracellular domain that can bind BlyS and/or APRIL.
[0025] A TACI-Ig fusion molecule can be administered to a patient according to any suitable
route of administration, including by not limited to orally, intravenously or subcutaneously.
[0026] TACI-Ig formulations useful for the methods of the invention can be prepared and
stored as a frozen, sterile, isotonic solution. Such formulations can include other
active ingredients and excipients such as, for example, sodium chloride, phosphate
buffer and sodium hydroxide or 0-phosphoric acid (pH 6.0). TACI-Ig formulations can
be administered to a patient in combination with other medicaments. Such medicaments
include but are not limited to NSAIDS (nonsteroidal anti-inflammatory drugs) both
over the counter and those requiring a prescription such as diclofenac sodium, indomethacin
diflunisal and nabumetone; anti-malarials such as hydroxychloroquine sulfate and chloroquine;
corticosteroids such as prednisone, hydrocortisone, and methylprednisolone; and immunosuppressives
such as azathioprine, cyclophosphamide, methotrexate, cyclosporine, and mycophenolate
mofetil, and IVIg, DHEA, and thalidomide.
[0027] Methods of the invention can be used in combination with other methods of treating
autoimmune diseases. Such other methods of treatment include, but are not limited
to surgery, acupuncture, physical therapy and gene therapy. TACI-Ig formulations can
be administered prior, simultaneously or subsequently to other methods of treatment.
[0028] TACI-Fc5 has been shown to inhibit BLyS activation of B cell proliferation in vitro.
Treatment of mice with TACI-Fc5 results in a partial block in B cell development that
has a minimal effect on B cell precursors in the bone marrow and other cell lineages
including peripheral blood T cells, monocytes and neutrophils. Transgenic mice engineered
to overexpress a soluble form of the TACI receptor in the blood produce fewer mature
B cells and show reduced levels of circulating antibody. The TACI-Fc5 transgenic mice
had normal numbers of cells in the thymus, bone marrow and mesenteric lymph node.
There were no significant differences in T cell populations in the thymus, lymph node
and spleen. (
Gross et al. Immunity 2001; 15(2): 289-302.)
[0029] Further, TACI-Ig can inhibit antigen-specific antibody production in an immune response
in mice whether administered during the primary response or the secondary response
to an antigen. In these studies, no effect on T cell response to ex vivo antigenic
challenge was observed. In an animal model of systemic lupus erythematosus, treatment
with TACI-Ig fusion proteins was effective in limiting the onset and progression of
the disease. (
Gross et al. Nature 2000; 404: 995-999). Similarly, in a mouse model of collagen-induced arthritis, TACI-Ig was able to
inhibit the development of collagen-specific antibodies and reduce both the incidence
of inflammation and the rate of occurrence of disease. (
Gross et al. Immunity 2001; 15(2): 289-302).
[0030] A composition comprising a TACI-Ig fusion molecule may be administered to a patient
once or may be administered to a patient repeatedly over a period of time. For example,
a patient may receive one subcutaneous injection of TACI-Ig molecules after which
his or her condition may be monitored. Patients who demonstrate improvement or at
least stabilization of their condition may be administered a TACI-Ig fusion molecule
repeatedly for an additional period of time. The additional period of time may be
from about 2 to about 52 weeks. For example, a patient may be administered three doses
of TACI-Ig fusion molecule during a four week interval. Alternately, a patient may
be administered seven doses of a TACI-Ig fusion molecule during a twelve week interval.
The administration of TACI-Ig molecules to a patient may be daily, bidaily, weekly,
bi-weekly, tri-weekly, monthly, bi-monthly, etc.
[0031] A TACI-Ig fusion molecule is administered to a patient in amount that is efficient
for treating the patient's condition. In one embodiment, the term "treating" in relation
a given disease or disorder, includes, but is not limited to, inhibiting the disease
or disorder, for example, arresting the development of the disease or disorder; relieving
the disease or disorder, for example, causing regression of the disease or disorder;
or relieving a condition caused by or resulting from the disease or disorder, for
example, relieving, preventing or treating symptoms of the disease or disorder. In
another embodiment, the amount may range from about 0.01 mg per 1 kg of patient's
body weight to about 20 mg per 1 kg of patient's body weight.
[0032] A fusion TACI-Ig molecule may be delivered in any suitable manner. In one embodiment,
the molecule is delivered by peritoneal injection. In another embodiment, the peritoneal
injection is via subcutaneous injection. In another embodiment, the peritoneal injection
is administered into the anterior abdominal wall. When more than one injection is
required to administer a dose, the injections can be administered a few centimeters
apart and relatively close together in time, for example as close as is reasonably
possible. For repeated drug administration, the site of administration on the anterior
abdominal wall can be rotated or alternated. Exemplary zones for subcutaneous injection
into the anterior abdominal wall include right upper external area, left lower external
area, right lower external area, left upper external area, median lower area as well
as right and left thighs and upper arms. Alternatively, a TACI-Ig fusion molecule
of the instant invention may delivered via intravenous injections or orally in a form
of tablets, caplets, liquid compositions or gels, etc.
[0033] B cells are currently thought to play an important role in SLE pathogenesis, through
both antibody-dependent and antibody-independent mechanisms. In addition to antibody
production, B cells secretenumerous cytokines, act as antigen presenting cells, and
serve a variety of effectorfunctions. Thus, B cells have emerged as rational targets
for drug development in SLE (
Browning JL., Nat Rev Drug Discov 2006;5:564-76).
[0034] Several B-cell-directed strategies have been proposed as possible therapies for SLE.
Some of these strategies are designed to eliminate B cells through the use of Bcell-directed
monoclonal antibodies (mAb) (
Leandro MJ, Edwards JC, Cambridge GI Ehrenstein MR, Isenberg DA. Arthritis Rheum 2002;46:2673-3;
Looney RJ, Anolik JH, Campbell D1 Felgar RE, Young F, Arend LJ, et al., Arthritis
Rheum 2004;50:2580-9;
Leandro MJ, Cambridge G, Edwards JC, Ehrenstein MR, Isenberg DA., Rheumatology 2005;44:1542-5;
Dorner T, Kaufman J, Wegener WA, Teoh N, Goldenberg DM, Burmester GR., Arthritis Res
Ther 2006;8:R74). While others interfere with B cell stimulation (
Baker KP, Edwards BM, Main SH, Choi GH, Wager RE, Halpern WG, et al. Arthritis Rheum
2003;48:3253-65;
Wallace DJ, Lisse J, Stohl W, McKay J, Boling El Merrill JT, et al., American College
of Rheumatology Annual Scientific Meeting, 2006;
Gross JA, Dillon SR, Mudri S, Johnston J, Littau A, Roque R, et al., Immunity 2001;
15:289-302) or seek to selectively target autoantibody-producing B cells (
Alarcon-Segovia D, Tumlin JA, Furie RA, McKay JD, Cardiel, MH, Strand V, et al., Arthritis
Rheum 2003;48:442-54;
Luger D, Dayan M, Zinger H, Liu JP, Mozes E. J Clin Immunol 2004;24:579-90;
Mauermann N, Sthoeger Z, Zinger H, Mozes E., Clin Exp lmmunol2004;137:513-20).
[0035] Attempts to inhibit B-cell stimulation have focused primarily on receptor-ligand
interactions that involve molecules called B lymphocyte stimulator (BLyS) and a proliferationinducing
ligand (APRIL). BLyS and APRIL are members of the tumor necrosis factor (TNF) family
of cytokines that are critical for B-cell survival and development after exit from
the bone marrow. BLyS and APRIL bind to common and distinct receptors. Both molecules
bind to transmembrane activator and calciummodulatorand cycolphilin ligand (CAML)
interactor (TACI) and B-cell-maturation antigen(BCMA), while BLyS also binds to B-cell-activating
factor belonging to the TNF Family -receptor (BAFF-R) and APRIL interacts with proteoglycans.
[0036] Mounting evidence in animal models and in humans supports an important role for BLyS
and APRIL in the development of autoimmune disease. Transgenic mice that overexpress
BLyS display B-cell expansion and polyclonal hypergammaglobulinemia (
Gross JA, Johnston J, Mudri S, Enselman R, Dillon S, Madden K, et al., Nature 2000:404:995-9;
Mackay F, Woodcock SA, Lawton P, Ambrose C, Baetscher M, Schneider P, et al., J Exp
Med 1999;190:1697-710;
Khare SD, Sarosi I, Xia XZ, McCabe S, Miner K, Solovyev I, et al., Proc Natl Acad
Sci 2000;97:3370-5). Some of these mice develop a lupus-like phenotype consisting of anti-double stranded
DNA (dsDNA) antibodies, immunoglobulin deposition in the kidneys, and accelerated
development of glomerular disease and levels of BLyS are elevated in lupus-prone NZBINZW
F1 (BIW) and MRL-lpr/lpr mice (
Stohl W, Xu D, Kim KS, Koss MN, Jorgensen TN, Deocharan B, et al., Arthritis Rheum
2005;52:2080-91). Studies in humans also suggest a role for BLyS and APRIL in systemic autoimmune
diseases. Patients with SLE have increased serum levels of BLyS that correlate positively
with levels of anti-dsDNA antibodies (
Zhang J, Roschke V, Baker K, Wang Z, Alarcon GS, Fessler BJ, et al., JImmunol 2001,166:6-10;
Cheema GS, Roschke V, Hilbert DM, Stohl W., Arthritis Rheum 2001;44:1313-19;
Stohl W, Metyas S, Tan SM, Cheema GS, Oamar B, Xu D, et al., Arthritis Rheum 2003;48:3475-86). Serum levels of APRIL are elevated in patients with SLE compared with healthy individuals
and patients with rheumatoid arthritis (
Koyama T, Tsukamoto H, Miyagi Y, Himeji D, Otsuka J, Miyagawa H, et al. Ann Rheum
Dis 2005;64:1065-7). BLyS and APRIL have been detected in the synovial fluid of patients with inflammatory
arthritis (
Tan SM, Xu D, Roschke V, Perry JW, Arkfeld DG, Ehresmann GR, et al., Arthritis Rheum
2003;48:982-92). These compelling observations in mice and humans have led to the developmentof
several BLyS antagonists. One of these agents is a recombinant fusion protein comprising
the extracellular domain of the TACl receptor joined to a human lgGl Fc domain (atacicept,
previously referred to as TACI-Ig). Atacicept blocks B-cell stimulation by both BLyS
and APRIL. Several lines of investigation provide support for the expectation that
atacicept will have potent effects in vivo. Firstly, transgenic mice that express
atacicept have few mature B cells and reduced immunoglobulin concentrations and treatment
with atacicept delays the onset and reduces the severity of arthritis in a mouse model
of collagen induced arthritis. The production of anti-collagen antibodies is also
suppressed (Gross JA, Dillon SR, Mudri S, Johnston J, Littau A, Roque R, et al., supra).
Thirdly, treatment of lupus-prone female B/W mice with atacicept delays the development
of proteinuria and increases survival (Gross JA, Johnston J, Mudri S, Enselman R,
Dillon S, Madden K, et al., supra). Finally, in a direct comparison of the efficacy
of murine atacicept and BAFF-R-lg (a BLyS-only inhibitor) in lupus-prone female BIW
mice, only atacicept reduced the serum levels of IgM, decreased the frequency of plasma
cells in the spleen, and inhibited the IgM response to a T-cell-dependent antigen,
suggesting a role for APRIL in these processes (
Ramanujam M, Wang X, Huang W, Liu Z, Schiffer L, Tao H, et al., J Clin Invest. 2006;
116:724-34). In light of these encouraging pre-clinical data, the present applicants examined
the biologic effects, pharmacokinetics, pharmacodynamics, and safety of atacicept
in clinical trials in patients with SLE.
[0037] In both exploratory Phase I trials described in Examples 1 and 2 below, atacicept
was well tolerated locally and systemically in patients with SLE. Clear signs of atacicept
biological activity in this prospective indication, very much in line with its mechanism
of action (MoA), have been observed.
[0038] According to the current concepts regarding the mechanism of action (MoA) for atacicept
and without being bound by theory, the inhibition of BLyS and APRIL results in effects
on B-cells, including non-specific and specific antibody secretion, which ultimately
affect various SLE-related biomarkers and clinical efficacy markers. As is typical
for Phase I studies, the attention in the current analysis is focused on the early
stages of the MoA cascade and specifically on the responses starting with early biomarkers
of BLyS and APRIL inhibition (such as the atacicept-BLyS complex), and biological
effects (such as the Ig levels).
[0039] Atacicept displayed multi-phasic, non-linear PK, characterized by a more than dose-proportional
increase in free drug exposure and saturated (less than dose-proportional) increase
in atacicept-BLyS complex exposure. Such behavior is expected and has been reported
in RA patients. It supports the hypothesis that the PK of atacicept are mediated by
its ligands. Overall the PK of atacicept, albeit non-linear, were consistent and predictable
across the doses, between single and multiple doses. The three PK markers of atacicept
behave very similarly in RA and SLE patients which indicates that the type of autoimmune
disease is not a major determinant of atacicept PK.
[0040] The continuing accumulation of atacicept-BLyS complex with multiple dosing (up to
four weekly doses for Cohorts 5 and 6, Study 1), coupled with the minimal accumulation
of free atacicept, provide evidence of the presence of considerable initial load of
soluble free BLyS and APRIL, both systemically and in the periphery. The elevated
baseline BLyS levels measured in these studies (compared to normal subjects from literature)
speak in favor of this hypothesis.
[0041] It is also very likely that, once the existing pre-dose equilibrium between the soluble
ligands and their receptors is disrupted by the administration of atacicept, complex
kinetic re-distribution processes between the blood circulation system, the lymphatic
system and the periphery compartments are initiated. This re-distribution involves
both the drug and its ligands and, given the size of the molecules involved, is likely
to take at least several weeks until a new equilibrium is established.
[0042] On the other hand, prolonged complex accumulation may imply significant rates of
endogenous generation of the free ligands (again both in the blood circulation and
in the peripheral tissues). Published data regarding the rate of serum BLyS increase
after rituximab administration (
Cambridge et al., Arthritis Rheum 2006;54:723-732) seem to provide additional evidence that endogenous BLyS production plays an important
role in BLyS inhibition and should be considered. The long time to steady state attainment
(beyond one month of weekly dosing) supports those hypotheses.
[0043] The saturable kinetics of atacicept was first observed and reported with single atacicept
doses applied to healthy volunteers and RA patients in previous Phase I studies and
indicates that BLyS (and APRIL) inhibition is saturable, i.e. increasing atacicept
exposure beyond the saturation point would bring about diminishing returns in terms
of BLyS (and eventually APRIL) binding. This phenomenon should be considered and exploited
when selecting therapeutic dosage regimens.
[0044] It should be emphasized that the appropriate saturation of BLyS (and APRIL) inhibition
needs to be maintained over time, and should be achieved by an appropriate atacicept
exposure pattern in time. The latter will require a dynamic balance between the complex
and largely uncharacterized processes of endogenous BLyS and APRIL generation and
redistribution and the created kinetic profile of atacicept. Such a balance can only
be achieved by an appropriate design of the dosing regimen in terms not only of dose
levels but also of dosing frequency.
[0045] A well-defined relationship between atacicept cumulative dose and Ig antibody response
has been established by non-compartmental methods; such a relationship was first detected
with single atacicept doses in healthy volunteers and with single and multiple atacicept
doses in patients with RA. In the current studies, all three Ig markers monitored
showed prompt decreases following the first dose of atacicept. Following four weekly
dosing, all three biomarkers of antibody response gradually and consistently decreased
toward steady state apparently without reaching it during the dosing period.
[0046] The observation that dosing frequency seems to play at least as important a role
as dose level in the response of all three biomarkers, first made in the RA study
is confirmed with the SLE data after subcutaneous administration (Study 1). In general,
the biomarkers behave very similarly at similar dose levels in both the SLE and RA
population, underlining the common root in the MoA of both indications based on BLyA
(and APRIL) inhibition.
[0047] Another interesting fact emerges from the comparison of the PK and biological activity
results between the two studies. Although neither of them has been designed to address
the subcutaneous availability question, a comparison of the partial and total areas
under the concentration - time curves (AUC's) of free and composite atacicept after
the similar subcutaneous and intravenous doses (Cohort 3, Study 1 versus Cohort 1
Study 2, and Cohort 4, Study 1 versus Cohort 2, Study 2) permits the derivation of
a crude estimate of the "mean" bioavailability. From Tables 2ab and 3ab these estimates
are approximately 35-40% for both the free and composite drug - a number that is not
outside of the ballpark figures for molecules with large molecular weights (
Porter and Charman, J Pharm Sci 2000; 89:297-310).
[0048] However, the inspection of the biological activity markers reveals that similar doses
yield similar biological activity irrespective of the route of administration, as
illustrated for IgM in Figure 19. At first take, the observation that 2.5 - 3 fold
different systemic exposures to the drug can lead to similar biological effects contradicts
the established paradigms; in the atacicept case, however, this phenomenon may be
well founded.
[0049] The current understanding of the absorption of large protein molecules after subcutaneous
administration states that proteins drain from the injection site into both the peripheral
lymph and the blood capillaries and the uptake into the lymphatics increases with
the molecular size. For drugs with MW commensurate with that of atacicept it can be
expected that as much as 70 - 80% of the subcutaneous dose might be expected to go
first into the peripheral lymph. However, the blood circulation and the lymphatic
systems are so closely inter-wined and connected, that the exchange of mass between
the blood and the lymph compartments should be fairly prompt and unimpeded, even for
large molecules. The latter is confirmed in the atacicept case by the comparatively
(for a MW of 73.4 KDa) rapid equilibration of the intravenous and subcutaneous PK
profiles.
[0050] These considerations lead to at least two possible, related, and hence by no means
mutually exclusive, explanations of the observed phenomenon. The "kinetic" explanation
hypothesizes that even with subcutaneous administration, sufficient amount of drug
transfers into the blood circulation to ensure adequate inhibition of BLyS and thus
to start the MoA cascade in the central compartment. It is well known that many biological
effects are delayed with respect to the underlying drug kinetics. Although in the
atacicept case the PD lag is not excessive (as evidenced by the prompt decrease in
the Ig markers after the first dose), it seems to be sufficient to render the PK lag
caused by the absorption almost irrelevant. This hypothesis is supported by the almost
identical atacicept:BLyS complex profiles in the same single dose cohorts of the subcutaneous
and intravenous studies (Figure 20), where the similarity is especially noted in the
first 7 days post administration.
[0051] The "pharmacodynamic" explanation is that both the blood circulation and the lymphatic
systems are "sites of action" for BLyS (and APRIL) inhibition and as such represents
targets for atacicept. With the intravenous route of administration, the drug is first
injected in the blood stream, and from there it distributes to the lymph and other
(target and non-target) peripheral tissues. With the subcutaneous route of administration,
the drug first drains into the lymphatic compartment and the blood stream in parallel,
and from the latter it distributes to the other (target and non-target) peripheral
tissues. In both cases penetration of the drug into the both sites of action is immediate
and prompt and results into similar biological activity profiles in each of them.
[0052] This interesting case supports the hypothesis that the mechanistic application of
the paradigm which dictates that assessment of the exposure to subcutaneous administered
protein drugs should be done via the systemic or "serum" bioavailability parameter
may be inappropriate, or incomplete at best. The rule "the greater the systemic bioavailability
- the greater the effect" may have important exceptions in this class of drugs.
[0053] The latter has important practical implications related to the development of therapeutic
regimen with atacicept. It becomes clear that the intravenous route may be only a
vehicle of delivering larger doses of the drug to the patient if such are necessary,
given that the magnitude of a subcutaneous dose may be limited by the injection volume
and the concentration of the dosing solution.
[0054] The good tolerability, marked biological activity of atacicept treatment in line
with its MoA, and the other positive trends observed in the two SLE Phase I studies
provide the rationale for further research of the drug in patients with SLE. According
to the modern drug development science paradigm at each step, newly generated information
should be appended to the already existing one, while the drug knowledge base is updated,
expanded and improved to be subsequently used for informed design of the next step
in a typical 'learn and confirm' cycle. In accordance to that paradigm, we chose to
observe and analyze a multitude of exposure (free and composite atacicept), specific
binding (atacicept-BLyS complex), biological activity (Igs and immune system cell
counts), and certain disease-related markers (anti-dsDNA antibodies) in the two early
studies with very complex design (sequential, dose escalating). Analyzing the wealth
of data generated in a rigorous way and extracting the information they contain will
enable us to define dose ranges and regimens for the further trials that will be needed
to characterize the safety profile of atacicept and to enhance the understanding of
its MoA, confirm initial indications of clinical efficacy, and define its optimal
clinical use.
Example 1 - Subcutaneous Administration of Atacicept
[0055] This phase Ib, double-blind, placebo-controlled, dose-escalating trial comprised
six cohorts (n=8 each, except for cohort 5, n='7) of patients treated with atacicept
or placebo in a 3:1 ratio. Cohorts 1-4 received a single subcutaneous dose of placebo,
or 0.3, 1, 3, or 9 mg/kg of atacicept. Cohorts 5 and 6 received four weekly doses
of placebo, or 1 or 3 mg/kg of atacicept (see Table 1). Patients were followed for
6 (cohorts 1-4) or 9 (cohorts 5 and 6) weeks. Outcome measures included: (i) systemic
and local tolerability of atacicept; (ii) frequency of adverse events (AEs); (iii)
pharmacokinetics and pharmacodynamics of atacicept, including effects on lymphocyte
subpopulations and Ig levels; and (iv) measures of SLE disease activity.
[0056] Patients with mild-to-moderate SLE were enrolled. Biologic activity of atacicept
was demonstrated by dose-dependent reductions in immunoglobulin levels and in mature
and total B cells. This effect was most pronounced in the repeat-dose cohorts and
was sustained throughout the follow-up period. There were no changes in the numbers
of T cells, natural killer cells, or monocytes. Mild injection-site reactions occurred
more frequently among the atacicept than the placebo group. There were no differences
in the frequency or type of adverse events, and no severe or serious adverse events
in patients treated with atacicept.
[0057] Pharmacokinetics were assessed by measuring serum levels of free atacicept (Table
2a), atacicept/BLyS complex (Table 3a), and composite atacicept (defined as free atacicept
+ atacicept-BLyS complex, Table 4a). Serum levels of each of these were quantified
using an enzyme-linked immunosorbant assay. Serum was incubated with a biotin-conjugated
mouse mAb specific for atacicept (free or total atacicept detection) (ZymoGenetics,
Inc., Seattle, WA) or biotin-conjugated goat polyclonal antibodies specific for either
BLyS or atacicept (atacicept/BLyS complex detection) (R & D Systems, Minneapolis,
MN), immobilized on a streptavidin-coated microplate (Adaltis, Montreal, Quebec).
The antibodies were incubated together with patient samples, standard, or control
samples diluted 1:10 for 1 hour. After washing, an atacicept-specific mouse mAb conjugated
to horseradish peroxidase (HRP) (to measure free atacicept or atacicept-BLyS complex)
or in the case of composite ELISA, mAbs against atacicept and BLyS (ZymoGenetics,
Inc.) are added and incubated at room temperature for 1 hour. In all three assays,
atacicept serum levels were detected and quantified using standard chemiluminescence
methods, i.e., after washing tetramethylbenzidine (TMB) was added as HRP substrate
(Sigma-Aldrich, St. Louis, MO). The reaction was halted after 20 minutes using 0.5
M sulfuric acid and the absorbance recorded at 450 nm. The analyte concentration of
a patient sample was recalculated using the standard curve, applying a polynomial
second order-fitting algorithm. All samples were measured in triplicate. Assay performance
criteria of a precision of <15% coefficient of variation (CV) for standard samples
and <20% for patient samples were accepted. The lower limits of quantification (LLOQ)
of the assays were 15.6 ng/mL for free atacicept, 5 U/mL for atacicept-BLyS complex
(1 U/mL corresponding to 1.82 ng/mL atacicept-0.44 ng/mL BLyS in a 3:1 molar ratio),
and 25 ng/mL for the composite analytes. The mean spiking recoveries performed to
test the accuracy for low, medium and high analyte concentrations in RA patient samples
corresponded to recovery rates of 82.5-97.0%, 93.9%, and 102.0-125.8% in the three
assays, respectively. Serum PK markers were sampled as follows: (i) for the single-dose
Cohorts 1-4 - at baseline and at 4, 8, 12 hours on the day of administration and thereafter
on study Days 2, 3, 4, 8, 15, 22, 29, and 43; (ii) for the multiple-dose arms in Cohorts
5 and 6 - at baseline and thereafter on study Days 8, 15, 22, 29, 36, 43, 64. In all
cohorts PK samples on dosing days were specified nominally as troughs.
[0058] Unbound BLyS concentrations were measured in serum at baseline. BLyS was measured
by ELISA. Biotinylated mAbs specific for BLyS were incubated together with patient
samples, standard or control samples (diluted 1:10) for 1 hour in streptavidin pre-coated
microplates. After washing, anti-BLyS, HRP-conjugated mouse mAbs were incubated at
room temperature for 1 hour. After washing, TMB was added as HRP substrate. The reaction
was stopped after 20 minutes using 0.5 M sulfuric acid and the absorbance recorded
at 450 nm. The analyte concentration of a patient sample was recalculated using the
standard curve applying a polynomial second order-fitting algorithm. All samples were
measured in triplicate. Assay performance criteria of a precision of <20% CV was an
accepted measurement in patient samples. The LLOQ was 1.56 ng/mL BLyS in serum. The
mean spiking recoveries for low, medium and high concentration of analytes in RA patient
samples corresponded to recovery rates of 101-113%.
[0059] Pharmacodynamics were assessed by measuring serum levels of immunoglobulins (IgG,
IgM, IgA), complement-3 (C3), and anti-nuclear antibodies (ANA), and by performing
flow cytometry analysis of lymphocyte subsets. Immunoglobulins and C3 were measured
using standard methods. ANA were measured using the Athena Multianalyte ANA test system
(Zeus Scientific Inc, Raritan, NJ, USA). IgG, IgM, and IgA were assessed in the blood
as markers of biological activity. The biomarkers were measured at baseline and at
8 hours on the day of administration (Cohorts 1-4 only), and thereafter on study Days
8, 15, 22, 29, 36, 43, and 64.
[0060] A panel of peripheral blood mononuclear cell types (B- and T-cell subsets, natural
killer [NK] cells and monocytes) was assessed in antibody-stained peripheral blood
samples, using four-color flow cytometry. The analysis included: total T cells (CD45+,
CD3+), T-helper cells (CD45+, CD3+, CB4+, CD8-), T-cytotoxic/suppressor cells (CD45+,
CD3+,CD4-, CD8+), total B cells (CDI 9+), mature B cells (CDI 9+, IgD+, CD27-), monocytes
(CD45+, CD3-, CD14+, CD56-), and NK cells (CD45+, CD3-, CD14-, CD56+). A contract
research organization (Esoterix, Groningen, The Netherlands) performed blood sample
processing, antibody staining, and acquisition, analysis and quality control of data.
We performed further analysis and quality control on B-cell subsets. For B-cell subsets,
the analysis gate was enlarged to include small and large lymphocytes, with the latter
being similar in size to monocytes.
[0061] Medical history was collected at inclusion and a physical examination was conducted
on a weekly basis. Hematologic, and serum chemistry profiles were performed on a weekly
basis and evaluated using the National Cancer Institute's Common Toxicity Criteria.
Blood samples for pharmacokinetic evaluations were collected on a weekly basis for
repeat-dose cohorts and on Day 1 at Hours 4 and 8, Days 2,3,4 and 8 and on a weekly
basis thereafter for the single-dose cohorts. Blood samples for pharmacodynamic evaluations
were drawn on a weekly basis in the repeat-dose cohorts and on Days 2, 3, 8, and then
on a weekly basis in the single-dose cohorts.
[0062] Electrocardiogram after D4 was performed on a bi-weekly basis in the single-dose
cohorts and on a weekly basis in patients receiving repeated doses of the study drug.
[0063] Although the study was not powered to determine the impact of treatment on disease
activity, the following disease activity measurements were obtained to provide preliminary
efficacy data. SELENA SLEDAI scores were determined at baseline and at Days 29 and
43 (cohorts 1-4) and at Days 22 and 64 (cohorts 5 and 6). Anti-dsDNA antibody and
C3 levels were measured at baseline and at Days 15, 29, and 43 (cohortsl-4), and at
Days 15, 22, 29,43, and 64 (cohorts 5 and 6).
[0064] The data analysis methods included subjecting concentration-time profiles were subjected
to non-compartmental analysis (NCA; WinNonLin software, version 5.0.1). All measurements
below the LLOQ were ignored for the NCA. Biomarker (IgM, IgG, or IgA) data were converted
into 'change from baseline' format and then the individual biomarker-time profiles
were also subjected to NCA. The resulting NCA-derived measures for exposure (PK) and
response were subsequently analyzed together to explore the existing exposure-response
relationships.
[0065] Evidence of non-linear pharmacokinetics, consistent with saturable binding pharmacokinetics
of ligand-receptor interactions, was demonstrated (Figures 1 and 2). Free and composite
atacicept concentration-time profiles displayed multiphasic pharmacokinetics with
fairly rapid absorption, Tmax approximately 24 hours after the first dose, and an
initial distribution phase lasting 7-14 days. Low accumulation of free atacicept was
observed in the repeat-dose cohort; the accumulation of composite atacicept was marginally
higher and the atacicept-BlyS complex was found to accumulate throughout the dosing
period.
[0066] Treatment with atacicept was associated with an initial, transient increase in mature
and total B cells followed by a sustained, dose-related reduction (Figure 3B). In
the single dose 3 mg/kg and 9 mg/kg groups and in the repeat-dose groups a reduction
from baseline of approximately 35% in mature B cells was seen at Day 29. In the single-dose
groups, this reduction was sustained through to Day 43; in the repeat-dose groups,
a reduction of approximately 60% was seen at Day 43 and was sustained at 45-60% through
to the last assessment at Day 64. The patterns observed for total B cells were similar
to those for mature B cells. In the 3 mg/kg single-dose group, a reduction from baseline
of approximately 30% in total B cells was seen at Day 29, which was sustained through
to Day 43. In the repeat-dose groups, reductions of approximately 40-50% were seen
at Day 43 and were sustained at 35-60% through to the last assessment at Day 64 (Figure
3B). There were no significant changes in the number of total, helper, or cytotoxic
T cells, NK cells, or monocytes.
[0067] Dose-dependent reductions in immunoglobulin levels were observed in atacicept treated
patients (Figure 3A and 3B, see also Table 5a). This effect was most notable in the
repeat-dose groups. IgM levels showed the greatest declines with treatment, reaching
nearly 50% at Day 43 in the 3 mg/kg repeat-dose group. IgA levels decreased by approximately
33% in the 3 mg/kg repeat-dose group at Day 29, and IgG levels decreased by approximately
16% in the 3 mg/kg repeat-dose group at Day 36. Nadirs occurred between Days 15 and
29 in the single-dose cohorts and between Days 29 and 43 in the repeat-dose cohorts.
[0068] Thereafter, values began to return towards baseline. Last observed values were approximately
5-30% below baseline in the single-dose cohorts (with the exception of the 0.3 mg/kg
group where IgM values were above baseline) and 8-65% below baseline in the repeat-dose
cohorts.
[0069] These results indicate that more frequent administration of smaller doses of atacicept
yield better biological activity than less frequent dosing with higher doses (Figure
7 and Figure 8).
Example 2 - Intravenous Administration of Atacicept
[0070] This phase Ib, double-blind, placebo-controlled, dose-escalating trial comprised
four cohorts (n=6 each) of patients treated intravenously with atacicept or placebo
in a 3:1 ratio. Cohorts 1-3 received a single dose of placebo, 3, 9, or 18 mg/kg of
atacicept. Cohort 4 received two doses of placebo or 9 mg/kg of atacicept, the second
dose occurring at three weeks after the initial dose (see Table 1). Outcome measures
included: (i) systemic and local tolerability of intravenous atacicept; (ii) frequency
of adverse events (AEs); (iii) pharmacokinetics and pharmacodynamics of intravenous
atacicept, including effects on lymphocyte subpopulations and Ig levels; and (iv)
measures of SLE disease activity. Subjects were evaluated over a 6-week (cohorts 1-3)
or 9-week (cohort4) period; subjects from cohorts 3 and 4 returned at study days 84
and 120 for PK and biomarker sampling. Serum PK markers were sampled as follows: (i)
for the single-dose Cohorts 1-3 - at baseline and at 0.25, 0.5, 4 hours on the day
of administration and thereafter on study Days 2, 3, 4, 8, 15, 22, 29, and 43; (ii)
for the multiple-dose Cohort 4 - at baseline and at 0.25, 0.5, 4 hours on the day
of the first administration and thereafter on study Days 8, 22, 22 (before the second
dose and 0,25 and 0.5 h after the second dose), 29, 36, 43, 64. Cohorts 3 and 4 have
PK measurements on study Days 85 and 120. In all cohorts PK samples on dosing days
were specified nominally as troughs. Unbound BLyS concentrations were measured in
serum at baseline. IgG, IgM, and IgA were assessed in the blood as markers of biological
activity. The biomarkers were measured at baseline, and thereafter on study Days 2,
3, 4, 8, 15 (Cohorts 1-3 only), 22, 29, 36, 43, and 64 (Cohort 4 only). Cohorts 3
and 4 have Ig measurements on study Days 85 and 120 as well.
[0071] As with Example 1, patients with mild-to-moderate SLE were enrolled and pharmacokinetics
were assessed by measuring serum levels of free atacicept (Table 2b), atacicept/BLyS
complex (Table 3b), and composite atacicept (defined as free atacicept + atacicept-BLyS
complex, Table 4b)). Biologic activity of atacicept was demonstrated by dose-dependent
reductions in immunoglobulin levels and in mature and total B cells (see Figure 11,
see also Figure 5b). This effect was most pronounced in the repeat-dose cohort and
was sustained throughout the follow-up period. There were no changes in the numbers
of T cells, natural killer cells, or monocytes. Mild administration site reactions
occurred more frequently among the atacicept than the placebo group. There were no
differences in the frequency or type of adverse events, and no severe or serious adverse
events in patients treated with atacicept. Comparison between the subcutaneous administration
(see Example 1) and intravenous administration routes revealed very similar pharmacokinetics
(nonlinear PK mediated by ligands) and a similar PK which was predictable and consistent
with single and multiple doses (Figures 9 and 10).
[0072] Although there did not appear to be an advantage to intravenous administration (despite
higher bioavailability with this route of administration, see Figure 4) these results
also support the conclusion that more frequent administration of smaller doses of
atacicept yield better biological activity than less frequent dosing with higher doses
(Figure 7 and Figure 8). These results also indicate that despite the lower bioavailability
of the drug using subcutaneous administration, the binding profile of the two methods
are very comparable (see Figure 7).
Table 1. Dosing arms in the Phase I SLE studies with atacicept.
| Study 1 - subcutaneous atacicept |
| Cohort |
Dose |
Administration |
Number of patients |
| 1 |
1x0.3 mg/kg |
Single dose |
6 active, 2 placebo |
| 2 |
1x1 mg/kg |
Single dose |
6 active, 2 placebo |
| 3 |
1x3 mg/kg |
Single dose |
6 active, 2 placebo |
| 4 |
1x9 mg/kg |
Single dose |
6 active, 2 placebo |
| 5 |
4x1 mg/kg |
4 weekly doses (QW) |
6 active, 2 placebo |
| 6 |
4x3 mg/kg |
4 weekly doses (QW) |
6 active, 2 placebo |
| Study 2 - intravenous atacicept |
| Cohort |
Dose |
Administration |
Number of patients |
| 1 |
1x3 mg/kg |
Single dose |
5 active, 1 placebo |
| 2 |
1x9 mg/kg |
Single dose |
5 active, 1 placebo |
| 3 |
1x18 mg/kg |
Single dose |
5 active, 1 placebo |
| 4 |
2x9 mg/kg |
2 doses 3 weeks apart |
5 active, 1 placebo |
Table 2a. Non-compartmental analysis-derived pharmacokinetic parameters for free atacicept,
Study 1.
| Estimated after the first dose |
| |
T½ (hours) |
Tmax (hours) |
Cmax (ng/mL) |
AUCINF (mg·h/L) |
AUC336 (mg·h/L) |
| Cohort 1, 0.3 mg/kg |
|
|
|
|
|
| Mean (SD) |
401 (477) |
28 (9.80) |
185 (145) |
30.4 (29.4) |
17.6(10.6) |
| Median |
204 |
24 |
136 |
19.1 |
14.1 |
| Cohort 2, 1 mg/kg |
|
|
|
|
|
| Mean (SD) |
452(219) |
18.7 (8.26) |
821 (525) |
108 (38.4) |
69.3 (29.1) |
| Median |
433 |
24 |
666 |
120 |
67.9 |
| Cohort 3, 3 mg/kg |
|
|
|
|
|
| Mean (SD) |
651 (218) |
28 (9.80) |
2600 (745) |
287 (55.6) |
218(47.2) |
| Median |
572 |
24 |
2830 |
293 |
239 |
| Cohort 4, 9 mg/kg |
|
|
|
|
|
| Mean (SD) |
642(218) |
32(12.4) |
6190 (3200) |
634(141) |
520(157) |
| Median |
653 |
24 |
5370 |
608 |
474 |
| Estimated after the last dose |
| Cohort 5, 4x1 mg/kg |
|
|
|
|
|
| Mean (SD) |
690 (230) |
N.E. |
N.E. |
147 (24.1) |
56.9 (9.80) |
| Median |
729 |
N.E. |
N.E. |
149 |
59.3 |
| Cohort 6, 4x3 mg/kg |
|
|
|
|
|
| Mean (SD) |
472 (157) |
N.E. |
N.E. |
209 (33.7) |
96.5 (34.5) |
| Median |
492 |
N.E. |
N.E. |
202 |
85.8 |
AUC336, area under the concentration-time curve from time 0 hours to time 336 hours; AUCINF, AUC from time 0 hours to infinity; Cmax, maximum concentration; SD, standard deviation; T½, terminal half-life; Tmax, time of the maximum concentration.
Last dose administered at 504 h.
N=6 SLE patients per cohort.
N.E. - Not estimated due to sampling scheme after the last dose. |
Table 2b. Non-compartmental analysis-derived pharmacokinetic parameters for free atacicept,
Study 2.
| Estimated after the first dose |
| |
T½ (hours) |
Tmax (hours) |
Cmax (ng/mL) |
AUCINF (mg·h/L) |
AUC336 (mg·h/L) |
| Cohort 1, 3 mg/kg |
|
|
|
|
|
| Mean (SD) |
743 (216) |
0.500 (0) |
39.7 (5.49) |
912(189) |
815(170) |
| Median |
642 |
0.500 |
38.6 |
953 |
848 |
| Cohort 2, 9 mg/kg |
|
|
|
|
|
| Mean (SD) |
722 (146) |
0.350 (0.137) |
198 (248) |
2040 (613) |
1930 (565) |
| Median |
765 |
0.250 |
91.7 |
1770 |
1680 |
| Cohort 3, 18 mg/kg |
|
|
|
|
|
| Mean (SD) |
796 (188) |
0.400 (0.137) |
289 (91.2) |
5010(743) |
4840 (713) |
| Median |
702 |
0.500 |
257 |
4880 |
4730 |
| Cohort 4, 2x9 mg/kg three weeks apart |
| Mean (SD) |
N.E. |
1.15 (1.60) |
140 (23.7) |
N.E. |
275 (220) |
| Median |
N.E. |
0.500 |
148 |
N.E. |
2620 |
| Estimated after the last dose |
| Cohort 4, 2x9 mg/kg three weeks apart |
| Mean (SD) |
748 (92.2) |
504.25 (0) |
109 (22.6) |
4320(1020) |
4110(971) |
| Median |
710 |
504.25 |
119 |
4700 |
4520 |
AUC336, area under the concentration-time curve from time 0 hours to time 336 hours; AUCINF, AUC from time 0 hours to infinity; Cmax, maximum concentration; SD, standard deviation; T½, terminal half-life; Tmax, time of the maximum concentration.
Last dose administered at 504 h.
N=6 SLE patients per cohort.
N.E. - Not estimated due to sampling scheme after the first dose. |
Table 3a. Non-compartmental analysis-derived pharmacokinetic parameters for composite
atacicept, Study 1.
| Estimated after the first dose |
| |
T½ (hours) |
Tmax (hours) |
Cmax (ng/mL) |
AUCINF (mg·h/L) |
AUC336 (mg·h/L) |
| Cohort 1, 0.3 mg/kg |
|
|
|
|
|
| Mean (SD) |
3710(5450) |
30(14.7) |
436 (300) |
1360 (2120) |
75.6 (36.5) |
| Median |
1270 |
24 |
324 |
319 |
61.0 |
| Cohort 2, 1 mg/kg |
|
|
|
|
|
| Mean (SD) |
807 (515) |
16(8.80) |
1160 (597) |
610(370) |
168 (47.1) |
| Median |
543 |
16 |
963 |
441 |
169 |
| Cohort 3, 3 mg/kg |
|
|
|
|
|
| Mean (SD) |
3040 (2770) |
32(12.4) |
3140 (935) |
2470(1620) |
400 (69.3) |
| Median |
2580 |
24 |
3130 |
2210 |
411 |
| Cohort 4, 9 mg/kg |
|
|
|
|
|
| Mean (SD) |
878 (256) |
32(12.4) |
8890 (4860) |
1770 (378) |
865 (199) |
| Median |
795 |
24 |
7150 |
1780 |
807 |
| Estimated after the last dose |
| Cohort 5, 4x1 mg/kg |
|
|
|
|
|
| Mean (SD) |
1410 (572) |
N.E. |
N.E. |
1570 (834) |
237 (50.4) |
| Median |
1610 |
N.E. |
N.E. |
1490 |
221 |
| Cohort 6, 4x3 mg/kg |
|
|
|
|
|
| Mean (SD) |
1500 (545) |
N.E. |
N.E. |
2530 (1340) |
386 (83.4) |
| Median |
1520 |
N.E. |
N.E. |
2070 |
389 |
AUC336, area under the concentration-time curve from time 0 hours to time 336 hours; AUCINF, AUC from time 0 hours to infinity; Cmax, maximum concentration; SD, standard deviation; T½, terminal half-life; Tmax, time of the maximum concentration.
Last dose administered at 504 h.
N=6 SLE patients per cohort; N.E. - Not estimated due to sampling scheme after the
last dose. |
Table 3b. Non-compartmental analysis-derived pharmacokinetic parameters for composite
atacicept, Study 2.
| Estimated after the first dose |
| |
T½ (hours) |
Tmax (hours) |
Cmax (ng/mL) |
AUCINF (mg·h/L) |
AUC336 (mg·h/L) |
| Cohort 1, 3 mg/kg |
|
|
|
|
|
| Mean (SD) |
2550 (1220) |
0.350 (0.137) |
57.3 (12.0) |
2870 (531) |
1180 (184) |
| Median |
2050 |
0.250 |
55.9 |
2650 |
1200 |
| Cohort 2, 9 mg/kg |
|
|
|
|
|
| Mean (SD) |
1560 (842) |
0.350 (0.137) |
348 (362) |
4590 (520) |
3210 (650) |
| Median |
1600 |
0.250 |
201 |
4430 |
2880 |
| Cohort 3, 18 mg/kg |
|
|
|
|
|
| Mean (SD) |
1080 (147) |
0.250 (0) |
411 (77.3) |
7470 (1380) |
5990 (863) |
| Median |
1100 |
0.250 |
446 |
7710 |
6240 |
| Cohort 4, 2x9 mg/kg three weeks apart |
| Mean (SD) |
N.E. |
1.05 (1.65) |
361 (334) |
N.E. |
4720 (2400) |
| Median |
N.E. |
0.250 |
251 |
N.E. |
4320 |
| Estimated after the last dose |
| Cohort 4, 2x9 mg/kg three weeks apart |
| Mean (SD) |
148 (750) |
504.25 (0) |
240 (69.4) |
8490 (2010) |
6390 (1200) |
| Median |
1140 |
504.25 |
272 |
8130 |
6390 |
AUC336, area under the concentration-time curve from time 0 hours to time 336 hours; AUCINF, AUC from time 0 hours to infinity; Cmax, maximum concentration; SD, standard deviation; T½, terminal half-life; Tmax, time of the maximum concentration.
Last dose administered at 504 h.
N=6 SLE patients per cohort.
N.E. - Not estimated due to sampling scheme after the first dose. |
Table 4a. Non-compartmental analysis-derived pharmacokinetic parameters for BLyS-atacicept
complex, Study 1.
| Estimated after the first dose |
| |
*T½ (hours) |
Tmax (hours) |
Cmax [kU/mL] |
*AUCINF (kU·h/L) |
AUC336 (kU·h/L) |
| Cohort 1, 0.3 mg/kg |
|
|
|
|
|
| Mean (SD) |
1240 (656) |
364 (126) |
161 (91.9) |
382 (390) |
38.5 (17.8) |
| Median |
1230 |
336 |
134 |
259 |
33.7 |
| Cohort 2, 1 mg/kg |
|
|
|
|
|
| Mean (SD) |
821 (704) |
260 (124) |
269 (89.9) |
362 (196) |
68.7 (24.1) |
| Median |
512 |
336 |
286 |
319 |
73.0 |
| Cohort 3, 3 mg/kg |
|
|
|
|
|
| Mean (SD) |
1250 (517) |
728 (330) |
316(30.4) |
727 (323) |
59.5 (13.3) |
| Median |
1420 |
840 |
315 |
735 |
55.9 |
| Cohort 4, 9 mg/kg |
|
|
|
|
|
| Mean (SD) |
6960 (6550) |
700 (223) |
369 (66.2) |
3680 (2890) |
69.9 (16.7) |
| Median |
6220 |
672 |
388 |
4330 |
72.7 |
| Estimated after the last dose |
| Cohort 5, 4x1 mg/kg |
|
|
|
|
|
| Mean (SD) |
2510 (2330) |
756 (92.0) |
460 (122) |
1700 (1330) |
139 (38.1) |
| Median |
1970 |
756 |
443 |
1260 |
134 |
| Cohort 6, 4x3 mg/kg |
|
|
|
|
|
| Mean (SD) |
7680 (13200) |
840 (184) |
668 (159) |
8050 (13700) |
201 (40.6) |
| Median |
2220 |
840 |
660 |
2450 |
199 |
AUC336, area under the concentration-time curve from time 0 hours to time 336 hours; AUCINF, AUC from time 0 hours to infinity; Cmax, maximum concentration; SD, standard deviation; T½, terminal half-life; Tmax, time of the maximum concentration.
Last dose administered at 504 h. N=6 SLE patients per cohort.
* T1/2 and AUCINF are not reliable estimates for this variable due to the terminal shape of the profiles. |
Table 4b. Non-compartmental analysis-derived pharmacokinetic parameters for BLyS-atacicept
complex, Study 2.
| Estimated after the first dose |
| |
*T½ (hours) |
Tmax (hours) |
Cmax (kU/mL) |
*AUCINF (kU·h/L) |
AUC336 (kU·h/L) |
| Cohort 1, 3 mg/kg |
| Mean (SD) |
8650 (159000) |
672 (206) |
0.297 (0.0412) |
35100 (63800 |
59.6 (10.2) |
| Median |
9800 |
672 |
0.300 |
4240 |
63.1 |
| Cohort 2, 9 mg/kg |
|
|
|
|
|
| Mean (SD) |
3790 (2320) |
605 (255) |
0.352 (0.0763) |
2040 (1230) |
61.0(11.4) |
| Median |
3770 |
504 |
0.342 |
2480 |
58.8 |
| Cohort 3, 18 mg/kg |
|
|
|
|
|
| Mean (SD) |
1800 (616) |
672 (206) |
0.454 (0.118) |
1460 (674) |
86.3 (20.0) |
| Median |
1570 |
672 |
0.452 |
1210 |
84.3 |
| Cohort 4, 2x9 mg/kg three weeks apart |
| Mean (SD) |
N.E. |
504 (0) |
0.414 (0.121) |
N.E. |
78.8 (17.8) |
| Median |
N.E. |
504 |
0.397 |
N.E. |
78.4 |
| Estimated after the last dose |
| Cohort 4, 2x9 mg/kg three weeks apart |
| Mean (SD) |
265 (3270) |
1008 (0) |
0.707 (0.343) |
2790 (2550) |
186 (38.0) |
| Median |
1140 |
1008 |
0.685 |
1740 |
195 |
AUC336, area under the concentration-time curve from time 0 hours to time 336 hours; AUCINF, AUC from time 0 hours to infinity; Cmax, maximum concentration; SD, standard deviation; T½, terminal half-life; Tmax, time of the maximum concentration.
Last dose administered at 504 h. N=6 SLE patients per cohort.
N.E. - not estimated
* T1/2 and AUCINF are not reliable estimates for this variable due to the terminal shape of the profiles. |
Table 5a. Non-compartmental analysis results for immunoglobulin (Ig)M, IgA, and IgG
biomarkers - Study 1.
| Cohort* |
IgM |
IgA |
IgG |
| Tmax (days) |
Max change (% of baseline) |
Tmax (days) |
Max change (% of baseline) |
Tmax (days) |
Max change (% of baseline) |
| Cohort 1, 0.3 mg/kg s.c. |
| Mean (SD) |
14.1 (17) |
2.82 (23.4) |
n.d. |
n.d. |
11.8 (15.7) |
-0.377 (17.8) |
| Median |
7 |
10.2 |
n.d. |
n.d. |
7.00 |
4.07 |
| Cohort 2, 1 mg/kg s.c. |
| Mean (SD) |
18.7 (13.0) |
19.4 (8.93) |
n.d. |
n.d. |
25.7 (14.5) |
11.1 (5.77) |
| Median |
17.5 |
16.5 |
n.d. |
n.d. |
24.5 |
12.1 |
| Cohort 3, 3 mg/kg s.c. |
| Mean (SD) |
23.3 (5.70) |
24.8 (3.81) |
n.d. |
n.d. |
29.2 (8.20) |
10.5 (1.25) |
| Median |
21.0 |
25.2 |
n.d. |
n.d. |
28.0 |
10.9 |
| Cohort 4, 9 mg/kg s.c. |
| Mean (SD) |
29.2 (8.20) |
37.9 (8.57) |
n.d. |
n.d. |
18.7 (7.20) |
14.7 (5.95) |
| Median |
28.0 |
37.2 |
n.d. |
n.d. |
21.0 |
15.9 |
| Cohort 5, 4x1 mg/kg s.c. QW |
| Mean (SD) |
31.0(11.3) |
29.2 (10.0) |
27.0 (10.2) |
23.1 (10.1) |
25.0 (11.3) |
11.5 (5.84) |
| Median |
35.0 |
31.0 |
28.0 |
20.7 |
28.0 |
14.4 |
| Cohort 6 4x3 mg/kg s.c. QW |
| Mean (SD) |
42.0 (11.7) |
50.4 (7.25) |
36.2 (2.90) |
34.9 (5.85) |
33.8 (6.90) |
17.5 (4.22) |
| Median |
42.0 |
49.8 |
35.0 |
32.9 |
35.0 |
17.8 |
| Placebo† |
|
|
|
|
|
|
| Mean (SD) |
13.5 (12.4) |
13.7 (15.3) |
14.0 (9.90) |
9.14 (7.06) |
11.0 (11.3) |
11.2 (13.5) |
| Median |
7.00 |
10.9 |
10.5 |
10.6 |
14.0 |
9.84 |
*Active-dose patients for Cohorts 1-6 (n=6)
†Placebo cohort, all placebo patients pooled together (n=12).
Tmax, time of the maximum depletion of Ig.
n.d. - no data. |
Table 5b. Non-compartmental analysis results for immunoglobulin (Ig)M, IgA, and IgG
biomarkers - Study 2.
| Cohort* |
IgM |
IgA |
IgG |
| Tmax (days) |
Max change (% of baseline) |
Tmax (days) |
Max change (% of baseline) |
Tmax (days) |
Max change (% of baseline) |
| Cohort 1, 3 mg/kg i.v. |
| Mean (SD) |
23.8 (12.7) |
34.2 (11.2) |
18.2 (14.5) |
19.0 (10.9) |
15.4 (7.70) |
13.9 (7.72) |
| Median |
21.0 |
39.4 |
14.0 |
14.9 |
21.0 |
12.2 |
| Cohort 2, 9 mg/kg i.v. |
| Mean (SD) |
25.2 (3.80) |
33.5 (5.64) |
21.0 (7.00) |
26.5 (3.43) |
21.0 (7.00) |
17.1 (3.86) |
| Median |
28.0 |
33.6 |
21.0 |
25.8 |
21.0 |
17.1 |
| Cohort 3, 18 mg/kg i.v. |
| Mean (SD) |
29.4 (7.70) |
35.3 (13.1) |
23.8 (6.30) |
29.8(5.71) |
19.6 (7.70) |
17.1 (1.96) |
| Median |
28.0 |
29.3 |
28.0 |
28.6 |
14.0 |
17.0 |
| Cohort 4, 2x9 mg/kg i.v. three weeks apart |
| Mean (SD) |
39.2 (6.30) |
42.3 (10.7) |
36.4 (7.70) |
35.9 (8.06) |
36.4 (7.70) |
23.2 (3.76) |
| Median |
42.0 |
41.2 |
42.0 |
37.5 |
42.0 |
24.0 |
| Placebo† |
|
|
|
|
|
|
| Mean (SD) |
10.2 (12.0) |
8.51 (5.14) |
21.5 (17.3) |
15.4 (16.1) |
10.0 (12.2) |
10.7 (7.14) |
| Median |
5.00 |
7.66 |
21.0 |
10.2 |
5.00 |
13.9 |
*Active-dose patients for Cohorts 1-4 (n=5)
†Placebo cohort, all placebo patients pooled together (n=4).
Tmax, time of the maximum depletion of Ig. |
References
[0073] References cited within this application, including patents, published applications
and other publications are herein incorporated by reference.
SEQUENCE LISTING
[0074]
<110> ZymoGenetics, Inc. Busby, Sharon Gross, Jane Visich, Jennifer Nestorov, Ivan
Munafo, Alain Papasouliotis, Orestis Pena Rossi, Claudia
<120> DOSING METHODS FOR TREATING AUTOIMMUNE DISEASES USING A TACI-IG FUSION MOLECULE
SUCH AS ATACICEPT
<130> 07-15PC
<150> 60/943,618
<151> 2007-06-13
<150> 61/024,031
<151> 2008-01-28
<160> 2
<170> PatentIn version 3.4
<210> 1
<211> 154
<212> PRT
<213> TACI
<400> 1

<210> 2
<211> 348
<212> PRT
<213> Human Immunoglobulin-Constant Domain Fc5
<400> 2
